The present invention relates to a power-saving method of controlling registration in mobile communication systems such as, for example, code division multiple access (CDMA) cellular telephone systems.
The mobile terminals in a mobile communication system register their location with the system from time to time, so that the system can page them quickly when the need arises. For CDMA cellular telephone systems, Interim Standard IS-95 of the Telecommunication Industries Association specifies, among other forms of registration control, a timer-based scheme in which an idle mobile terminal sends a registration message to the system at regular intervals, which are designated by the system. The registration message contains information that the system can analyze to determine the location of the mobile terminal. The system stores the mobile terminal's location in a data base, which is updated as new registration messages arrive.
A problem with this registration control scheme is that while standing by to receive calls, a mobile terminal continues to send registration messages at the designated regular intervals, even if the mobile terminal is not actually moving. Since the registration messages are transmitted at comparatively high power, much power is dissipated in this way, causing unnecessary battery drain and shortening the time the mobile can continue operating in standby. System resources are also consumed in unnecessary data-base updates.
This problem is not limited to CDMA cellular telephone systems; it can occur in any type of mobile communication system that performs timer-based location registration.